Engineered Materials for Drill Rod Applications

ABSTRACT

Implementations described herein comprise drill rods comprising an integral tubular metallic body having a first ends, an opposing second end, and an elongate midbody extending along a central axis between the first and second ends and where the metallic body defines a central bore that extends along the central axis and has a body inner surface and at least one body bore diameter. In further aspects, the drill rods further comprise an underlying tubular composite lining that has a lining outer surface that is connected to at least the body inner surface of the midbody of the metallic body, the composite lining defining an operative bore that extends along the central axis and has at least one operative bore diameter.

BACKGROUND OF THE INVENTION

1. The Field of the Invention

Implementations of the present invention relate generally to components and systems for drilling. In particular, implementations of the present invention relate to drill components comprising fiber-composite reinforced midbodies.

2. Background

Oilfield, exploration, and other drilling technologies make extensive use of drill string components such as drill rods in conventional percussive and coring drilling applications. Drill rods typically comprise a threaded box end and threaded a pin end joined by a midbody. Adjacent drill rods are joined together by coupling the threaded box end to the complementarily threaded pin end to form a tool joint. Conventionally, in drilling, a plurality of drill rod sections, which are each typically about twenty-five feet long more or less, are coupled together in series to form a drill string. As the depth of the bore increases, the drill string is correspondingly lengthened by the addition of drill rod sections at the drill rig. The drill string operatively couples a bottom hole assembly having a boring tool to a motor at the drill rig on the surface. The motor transmits axial impact and/or torque via the drill string to the bottom hole assembly and, thus, the boring tool. The forces transmitted by the motor combined with the weight of the drill string causes the boring tool to wear away the underlying material.

In accordance with convention, each drill rod section is made hollow so that the drill string can serve as a conduit for drilling fluid, such as compressed air, which is discharged through the drill bit at the bottom of the well. This drilling fluid picks up cuttings from the drill bit and carries them upwardly to the well top on the outside of the drill string. Compressed air, when used as the drilling fluid, can also be used to operate the drill bit, as in percussion drilling; or the drill bit can be operated directly by drill string rotation.

Conventional drill rods are hollow pipes that are subjected to high levels of at least one of axial and torsional loads during a drilling operation. Each drill rod in an assembly must support its own weight as well as the lengths of drill rod positioned above it in a drill string. Also, the drill rods can be subjected to high levels of impact and torsional and bending stresses during the drilling operation. In percussive drilling, drill rods and other drill components are subject to high levels of impact, local-working, and bending stresses associated with the drilling process. Drill rods typically fail at the joints when failure occurs.

One limitation on the drilling of relatively deep wells is the drill string weight, which of course becomes greater and greater as the bore depth is increased. Historically, drill rod sections have been made of structural steel or alloys of structural steel; but with the deeper bores now being drilled, the heavier drill strings can impose fatiguing loads on the component drill rod sections and on the equipment used to rotate and raise and lower the drill string.

In order to lessen the loads placed on the drill rod joints it is desirable to minimize the overall weight of the individual drill rods while retaining the desired range of load, torsional and impact capacity. It is currently known to reduce the weight of individual drill rod sections by forming drill rod sections in which the wall thickness of a middle portion of the midbody has a reduced cross-sectional thickness relative to the wall thickness proximate the respective box and pin ends. However, the thinner cross-sectional widths of the walls of the midbody of the drill rod section results in a direct loss of load, torsional and impact capacity of the drill rod.

Accordingly, a need exists for improved drill string components that preserve load, torsional and impact capacity but minimize the weight of the drill string component.

SUMMARY

It is to be understood that this summary is not an extensive overview of the disclosure. This summary is exemplary and not restrictive, and it is intended to neither identify key or critical elements of the disclosure nor delineate the scope thereof. The sole purpose of this summary is to explain and exemplify certain concepts of the disclosure as an introduction to the following complete and extensive detailed description.

In certain aspects, the present disclosure provides for drill rods comprising an integral tubular metallic body having a first ends, an opposing second end, and an elongate midbody extending along a central axis between the first and second ends and where the metallic body defines a central bore that extends along the central axis and has a body inner surface and at least one body bore diameter. In further aspects, the drill rods comprise an underlying tubular composite lining that has a lining outer surface that is connected to at least the body inner surface of the midbody of the metallic body, the composite lining defining an operative bore that extends along the central axis and has at least one operative bore diameter.

Additional features and advantages of exemplary implementations of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of such exemplary implementations. The features and advantages of such implementations may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features will become more fully apparent from the following description and appended claims, or may be learned by the practice of such exemplary implementations as set forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate aspects and together with the description, serve to explain the principles of the methods and systems.

FIG. 1 illustrates a longitudinal cross-sectional view of one aspect of a drill string component having a fiber-composite reinforced midbody.

FIG. 2 illustrates a longitudinal cross-sectional view of another aspect of a drill string component having a fiber-composite reinforced midbody and an increasing body bore diameter.

FIG. 3 illustrates a longitudinal cross-sectional view of another aspect of a drill string component having a fiber-composite reinforced midbody and a V-shaped body bore diameter.

DETAILED DESCRIPTION

The present invention can be understood more readily by reference to the following detailed description, examples, drawing, and claims, and their previous and following description. However, before the present devices, systems, and/or methods are disclosed and described, it is to be understood that this invention is not limited to the specific devices, systems, and/or methods disclosed unless otherwise specified, as such can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting.

The following description of the invention is provided as an enabling teaching of the invention in its best, currently known aspect. To this end, those skilled in the relevant art will recognize and appreciate that many changes can be made to the various aspects of the invention described herein, while still obtaining the beneficial results described herein. It will also be apparent that some of the desired benefits described herein can be obtained by selecting some of the features described herein without utilizing other features. Accordingly, those who work in the art will recognize that many modifications and adaptations to the present invention are possible and can even be desirable in certain circumstances and are a part described herein. Thus, the following description is provided as illustrative of the principles described herein and not in limitation thereof.

Reference will be made to the drawings to describe various aspects of one or more implementations of the invention. It is to be understood that the drawings are diagrammatic and schematic representations of one or more implementations, and are not limiting of the present disclosure. Moreover, while various drawings are provided at a scale that is considered functional for one or more implementations, the drawings are not necessarily drawn to scale for all contemplated implementations. The drawings thus represent an exemplary scale, but no inference should be drawn from the drawings as to any required scale.

In the following description, numerous specific details are set forth in order to provide a thorough understanding described herein. It will be obvious, however, to one skilled in the art that the present disclosure may be practiced without these specific details. In other instances, well-known aspects of drill string technology have not been described in particular detail in order to avoid unnecessarily obscuring aspects of the disclosed implementations.

As used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

“Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.

Throughout the description and claims of this specification, the word “comprise” and variations of the word, such as “comprising” and “comprises,” means “including but not limited to,” and is not intended to exclude, for example, other additives, components, integers or steps. “Exemplary” means “an example of” and is not intended to convey an indication of a preferred or ideal aspect. “Such as” is not used in a restrictive sense, but for explanatory purposes.

Disclosed are components that can be used to perform the disclosed methods and systems. These and other components are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc. of these components are disclosed that while specific reference of each various individual and collective combinations and permutation of these may not be explicitly disclosed, each is specifically contemplated and described herein, for all methods and systems. This applies to all aspects of this application including, but not limited to, steps in disclosed methods. Thus, if there are a variety of additional steps that can be perdefined it is understood that each of these additional steps can be perdefined with any specific aspect or combination of aspects of the disclosed methods.

Implementations described herein are directed toward drill string components that preserve load, torsional and impact capacity but minimize the weight of the drill string component as well as methods of using and manufacturing the same. In certain aspects, the present disclosure provides for drill rods comprising an integral tubular metallic body having a first end, an opposing second end, and an elongate midbody extending along a central axis between the first and second ends and where the metallic body defines a central bore that extends along the central axis and has a body inner surface and at least one body bore diameter. In further aspects, the drill rods further comprise an underlying tubular composite lining that has a lining outer surface that is connected to at least the body inner surface of the midbody of the metallic body, the composite lining defining an operative bore that extends along the central axis and has at least one operative bore diameter.

In certain aspects, implementations of the present disclosure provide for improved drill string components that preserve load, torsional and impact capacity while minimizing the weight of the drill string component. In other aspects, implementations of the present disclosure maintain a continuous metal exterior surface and, thus, avoid any abrasive wear of the composite lining against the drilled hole or cuttings resulting therefrom.

In other aspects of the present disclosure, maintaining a continuous metal rod for threading drill string components together and limiting the use of composite material to an interior lining avoids the alternative of assembling drill string components from dis-similar materials. For example and without limitation, creating a drill string component by non-mechanical bonding of steel or steel alloy to, for example, a composite or even an aluminum midbody can create a weak and/or brittle interface or joint that can be insufficient to withstand the impact, vibration and fatigue loading associated with typical drill string loading conditions. Additionally, there can also be insufficient annular space available to allow a combination of mechanical and chemical bonding in certain drilling applications such as, for example and without limitation, wireline core drilling and the like. However, one skilled in the art will appreciate that there is enough annular space to enable feasibility of such an approach in other applications, such as, for example and without limitation, energy, oil and like drilling applications.

In yet other aspects, implementations of the present invention provide for corrosion protection in, for example and without limitation, percussive drilling applications. One skilled in the art will appreciate that corrosive and/or acidic drilling fluids can be pumped through drill rod interiors and this can lead to stress corrosion fatigue failures involving crack initiation on the inner diameter of the drill rod interior. One skilled in the art will appreciate that the present disclosure comprises drill string components having a composite lining that provides increased protection against corrosion and can reduce or eliminate stress corrosion fatigue failures.

In even other aspects, implementations of the present disclosure provide for more accurate drilling results by increasing the stiffness of the drill string components and, thus, the drill string. In light of the present disclosure, one skilled in the art will appreciate that the increased stiffness associated with the composite lining can result in an increased stiffness of the drill string component. This increased stiffness can reduce the deflection of the drill string and, correspondingly, the drilled hole, thereby providing more accurate drilling results such as, for example and without limitation, improved blasting efficiency when drilling blast holes, improved targeting in mineral exploration, and the like.

Reference will now be made to the drawings to describe various aspects of one or more implementations of the invention. It is to be understood that the drawings are diagrammatic and schematic representations of one or more implementations, and are not limiting of the present disclosure. Moreover, while various drawings are provided at a scale that is considered functional for one or more implementations, the drawings are not necessarily drawn to scale for all contemplated implementations. The drawings thus represent an exemplary scale, but no inference should be drawn from the drawings as to any required scale.

In the following description, numerous specific details are set forth in order to provide a thorough understanding described herein. It will be obvious, however, to one skilled in the art that the present disclosure may be practiced without these specific details. In other instances, well-known aspects of drill string technology have not been described in particular detail in order to avoid unnecessarily obscuring aspects of the disclosed implementations.

Turning now to FIGS. 1-3, various exemplary implementations of a drill string components that preserve load, torsional and impact capacity while minimizing the weight of the drill string component are illustrated.

As illustrated in FIG. 1, a drill rod 100 comprises an integral tubular metallic body 101 further comprising a first end 102, an opposing second end 104, and an elongate midbody 106 extending along a central axis 108 between the first end 102 and second end 104. The first end 102 of the tubular metallic body 101 can comprise a box end and a second end 104 can comprise a pin end. Alternatively, both the first end 102 and the second end 104 can form a box end or both form a pin end. The metallic body 101 can further define a central bore 110 that extends along the central axis 108 and has a body inner surface 112 and at least one body bore diameter 114. In further aspects, an underlying tubular composite lining 116 having a lining outer surface 118 can be connected to at least a portion of the body inner surface 112 of the midbody 106 of the metallic body. The composite lining 116 can define an operative bore 120 that can extend along the central axis and can have at least one operative bore diameter 122. In an additional aspect, the composite lining can extend to a terminal end of the second end 104 or pin end of the tubular metallic body 101.

In one aspect illustrated in FIG. 1, the drill rod 100 can have midbody 106 having a substantially constant body bore diameter 114 and a substantially constant operative bore diameter 120. Here, the cross-sectional thickness of at least the composite lining 116 is substantially constant across at least the body inner surface 112 of the midbody 106.

In other aspects illustrated in FIG. 1, the body bore diameter 114 of the metallic body 101 can comprise a first bore diameter 114 a and a second bore diameter 114 b, wherein the first bore diameter can be less than the second bore diameter. In one aspect, the second bore diameter 114 b extends at least the length of the midbody 106. In an alternative aspect, the second bore diameter can extend the combined length of the midbody 106 and the second end 104. In a further aspect, the composite lining 116 can have a substantially constant cross-sectional thickness and can be configured to extend the longitudinal length corresponding to the second bore diameter 114 b. Here, the liner cross-sectional thickness plus the tubular metallic body wall thickness is substantially constant across at least longitudinal length corresponding to the midbody 106.

In other aspects illustrated in FIG. 2, the body bore diameter 114 of at least the midbody 106 can increase from a first bore diameter 114 a to a second bore diameter 114 b. In a further aspect, the body bore diameter 114 can increase from a first bore diameter to a second bore diameter across the combined lengths of the midbody 106 and the second end 104. In a further aspect, the composite lining 116 can have a constant cross-sectional thickness and can be configured to extend the longitudinal length corresponding to at least the midbody 106 and, optionally, the second end 104. In an alternative aspect, cross-sectional thickness 124 of the composite liner 116 can vary such that the sum of the composite lining cross-sectional thickness 124 and the midbody cross-sectional thickness 126.

In yet other aspects illustrated in FIG. 3, the tubular metallic body can further comprise a tubular wall and the body bore diameter 114 of the metallic body 101 can comprise a first bore diameter 114 a and a second bore diameter 114 b, wherein the first bore diameter can be less than the second bore diameter. Here, the body inner surface 112 of the midbody 106 can be configured to taper from both the respective first end 102 and second end 104 both having a first bore diameter 114 a to a middle portion 128 of the midbody having a second bore diameter 114 b. In a further aspect, the composite lining 116 can have a constant cross-sectional thickness and can be configured to extend the longitudinal length corresponding to the midbody 106. In an alternative aspect, cross-sectional thickness of the composite liner 116 can vary such that the sum of the cross-sectional thickness of the composite lining 106 and the cross-sectional thickness of at least the midbody 106 at any point can be substantially constant.

The underlying composite linings of the present disclosure can comprise a fiber-impregnated composite material. In one aspect, the fiber-impregnated composite material can comprise carbon fiber. In further aspects, the fiber-impregnated composite material can comprise a known quantity of pitch-based carbon fiber. In other aspects, the composite material can comprise a carbon-fiber containing polymer material. It is further contemplated that the composite material can comprise unidirectionally-oriented carbon fiber. One skilled in the art will appreciate, in light of the present disclosure, that unidirectional fibers can be selectively configured to provide increased stiffness or increased torsional strength. In one illustrative example, a composite material containing carbon fiber aligned with the central axis 108 can be used to provide increased stiffness of the drill rod. In another illustrative example, a composite material containing carbon fiber oriented at an angle relative to the central axis 108 can be used to provide increased torsional strength of the drill rod. In other aspects, the fibers can be at least bi-directionally-oriented with respect to the central axis 108. In an illustrative example, the fibers can be cross-laid to form spirals, imparting the drill rod with both increased stiffness and increased torsional strength.

In another aspect, a method of manufacturing drill string components that preserve load, torsional and impact capacity but minimize the weight of a drill string component comprises the steps of (i) providing a drill rod 100 having an integral tubular metallic body 101 further comprising a first end 102, an opposing second end 104, and an elongate midbody 106 extending along a central axis 108 between the first end 102 and second end 104 and wherein the metallic body 101 further defines a central bore 110 that extends along the central axis 108 and has a body inner surface 112 and at least one body bore diameter 114; (ii) providing a rolled sheet of composite lining 116 containing a known quantity of pitch-based carbon fiber and impregnated with an adhesive material such as, for example and without limitation, a resin or the like; (iii) inserting the rolled sheet of composite lining 116 into the metallic body 101 such that the composite lining does not overlap at least the first end 102; (iv) causing the rolled sheet of composite lining to deploy such that its outer surface 118 contacts at least a portion of the body inner surface 112 of the metallic body; and (v) curing the composite material to connect the composite lining outer surface 118 to the metallic body inner surface 112.

Accordingly, FIGS. 1-3, and the corresponding text, provide a number of different drill string components that preserve load, torsional and impact capacity but minimize the weight of a drill string component. In addition to the foregoing, implementations described herein can also be described in terms acts and steps in a method for accomplishing a particular result. For example, a method comprising manufacturing drill string components that preserve load, torsional and impact capacity but minimize the weight of a drill string component is described above with reference to the components and diagrams of FIGS. 1 through 3.

Thus, implementations of the foregoing provide various desirable features. For instance, the drill string components having composite liners provided herein can provide increased stiffness of the component and the resulting drill string, enabling more accurate drilling results. In another instance, the present disclosure limits composite elements to linings only and maintains a continuous metal rod on the exterior; thus avoiding the need to join dis-similar materials along the length of the drill string component as well as exposing the composite liner to abrasive wear against the drilling hole or the cuttings. In another instance, the interior composite lining protects against potential corrosion as corrosive and/or acidic drilling fluids are pumped through the interior of the drill string component.

The present invention can thus be embodied in other specific forms without departing from its spirit or essential characteristics. The described aspects are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope. 

What is claimed is:
 1. A drill string component, comprising: an integral tubular metallic body comprising a first end, an opposing second end, and an elongate midbody extending along a central axis therebetween the first and second ends, the metallic body defining a central bore that extends along the central axis and has a body inner surface and at least one body bore diameter; an underlying tubular composite lining that has a lining outer surface that is connected to at least the body inner surface of the midbody of the metallic body, the composite lining defining an operative bore that extends along the central axis and has at least one operative bore diameter.
 2. The drill string component of claim 1, wherein the first end comprises a box end.
 3. The drill string component of claim 1, wherein the second end comprises a pin end.
 4. The drill string component of claim 3, wherein the underlying tubular composite lining extends to a terminal end of the pin end of the hollow body.
 5. The drill string component of claim 1, wherein the underlying tubular composite lining comprises fibers having a unidirectional orientation.
 6. The drill string component of claim 5, wherein the unidirectional orientation further comprises an axial orientation.
 7. The drill string component of claim 5, wherein the unidirectional orientation further comprises an angled orientation.
 8. The drill string component of claim 1, wherein the underlying tubular composite lining comprises fibers that are cross-laid to form spirals.
 9. The drill string component of claim 1, wherein the body bore diameter of the body is substantially constant across an elongate length of the midbody.
 10. The drill string component of claim 9, wherein the operative bore diameter is substantially constant across the elongate length of the midbody.
 11. The drill string component of claim 1, wherein at least one body bore diameter comprises a first bore diameter and a second bore diameter, and wherein the first bore diameter is less than the second bore diameter.
 12. The drill string component of claim 11, wherein the tubular metallic body has a tubular wall, wherein the body inner surface tapers to a middle portion of the midbody from both respective first and second end portions; and wherein the inner surface of the middle portion has the second bore diameter and the respective first and second end portions have the first bore diameter.
 13. The drill string component of claim 12, wherein the underlying composite lining has a lining cross-sectional thickness, and wherein the lining cross-sectional thickness is substantially constant across an elongate length of the midbody.
 14. The drill string component of claim 12, wherein the tubular wall has a wall cross-sectional thickness and the underlying composite lining has a lining cross-sectional thickness, and wherein the cross-sectional thickness of the wall of the tubular metallic body and the connected tubular composite lining is substantially constant across an elongate length of the midbody.
 15. The drill string component of claim 12, wherein the body bore diameter increases across the entire length of the tubular midbody
 16. The drill string component of claim 16, wherein the composite lining has a thickness and wherein the thickness of the composite lining is constant across the length of the tubular midbody.
 17. The drill string component of claim 16, wherein the tubular metal wall has a thickness and the composite lining has a thickness, and wherein the sum of the thickness of the tubular metal wall and the thickness of the composite lining are constant across the length of the midbody.
 18. The drill string component of claim 1, wherein the drill string component is configured to be a percussive drill rod.
 19. The drill string component of claim 1, wherein the drill string component is configured to be a coring drill rod.
 20. The drill string component of claim 1, wherein both the first end and the second end comprise a box end.
 21. The drill string component of claim 1, wherein both the first end and the second end comprise a pin end. 